HETEROCYCLIZATION OF COMPOUNDS CONTAINING DIAZO AND CYANO GROUPS. 6. THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF CYCLIZATION OF 2-CYANO-2-DIAZOACETAMIDES TO 5-HYDROXY-1,2,3-TRIAZOLE-4-CARBONITRILES

Abstract

A series of N-alkyl‑ and N-aryl-2-cyano-2-diazoacetamides was synthesized by the reaction of 2-amino-2-cyanoacetamides with sodium nitrite in hydrochloric acid. The mechanism of their heteroelectro-cyclization to 5-hydroxy-1,2,3-triazoles was investigated kinetically and theoretically by the B3LYP/6-31 + G* method. The conclusion was made on the basis of the determined activation energy of the cyclization process, reaction parameters r, and kinetic isotope effects, that there is a difference between the mechanisms of cyclization of the N-alkyl and N-aryl derivatives of 2-cyano-2-diazoacetamide; cyclization of the N-alkyl derivatives takes place by a monorotatory mechanism, while cyclization of the N‑aryl derivatives takes place by a mechanism where one of the stages is heteroelectrocyclization of 2‑diazoacetimidates.

Authors: Yu. Yu. Morzherin, M. Yu. Kolobov, V. S. Mokrushin, M. Brauer, E. Anders, and V. A. Bakulev.

English Translation in Chemistry of Heterocyclic Compounds, 2000, 36 (1), pp 22-36

http://link.springer.com/article/10.1007/BF02256840